Update signature deploy examples

## Summary
Currently the examples for deploying signature mode smart contracts call goal directly. They would be more helpful if they used the Python SDK, since it can now support calling the compile endpoint.

## Scope
Need to update `examples/signature/periodic_payment_deploy.py` and `examples/siguature/recurring_swap_deploy.py` and test that they still work correctly.

## Urgency
These are the only examples of how to deploy stateless PyTeal smart contracts, so it would help developers if they used the current best practices. That being said, more of a nice-to-have. Not much of a blocker currently